Release of phosphorus and metals from soils and sediments during dispersion

The authors determined the P, Al, Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn released from soils and river bottom sediments to the supernatant liquid during dispersion by ultrasound and end-over-end shaking techniques. The ratios of the elements in the supernatant to the total acid-digestible elements on the solid phase varied from 1.0 to 7.3% for soils and 0.3 to 2.0% for sediments, using ultrasound, and 0.05 to 2.6% for soils and 0.03 to 0.7% for sediments, using the shaking method. The ratio provides an estimate of the analytical error caused by dispersion during particle size fractionation. Furthermore, the ratio may indicate the extent of release of elements to the overlying water during resuspension or transport of sediments. Cadmium is the element most easily removed from soils and sediment surfaces.